Special troughs have come into increasing use to avoid dropping and spilling when applying liquids, such as paints, varnishes, oils and the like, on different objects with tools such as brushes, rollers and the like. Thereby one has been forced to fill the trough with liquid from the original container. This development has been particularly noticeable in painting work, and accordingly the continued description will deal primarily with painting and particularly painting rollers. However, it is obvious that the same problem and conditions apply for other liquids and tools.
In painting walls and ceilings with rollers a special trough is normally used, in which the paint has been poured so that it can be taken up by the roller. The trough is formed with a paint removal side portion intended to assist in the removal of excess paint. It is also known for professional painters to dip the roller directly into the original can of paint and to remove the excess paint from the roller by rolling it a few times against a sheet of masonite. These known methods result in waste of paint and time.
From the patent literature, e.g. the German Patent No. 2 140 189, it is also known to utilize a special, completely flat slab-like insert which has been placed buoyantly on the surface of the paint in the container in which the paint is kept during painting. The technical function of the known device can be questioned, however, since it tips over easily and has a tendency to bind against the walls of the container. Other disadvantages with the known device are that due to the holes or slits in the insert it presses up paint, which, when a roller is to be given more paint, will be pressed in front of the roller as a kind of bow wave and thereby inhibit uniform take-up of paint. The roller will thus take up excess paint in patches, and particularly at its short ends. This paint cannot be scraped off but forms drops during painting.